Skin clamp



G. W. PERIMAN SKIN CLAMP March 9, 1943.

Filed Dec. 31, 1941 Glenn D. Penzman IN E EN TOR.

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Patented Mar. 9, 1943 UNITED STATES PATENT OFFICE SKIN CLAMP Glenn W. Periman, Los Angeles, CaIiL assignor to Aircraft Tools Inc., Los Angeles, Callt, a corporation of California Application December 31, 1941, Serial No. 425,089 I 1 Claim.

The present invention relates generally to plate fastening devices, commonly known as skin clamps, and used through certain openings of previously perforated metal plates to hold the same with their perforations in alignment while rivets are fixed through other perforations, after which the clamps are removed to permit rivets to be fixed through the openings previously occupied by the clamps.

It is apparent that, in addition to strength and durability, important features of such skin clamps include ready manipulation and adaptability to quick, easy insertion in and removal from effective position. With this in mind, it is an important object of the present invention to provide a skin clamp which is simple, strong and durable, and which may be manually applied and removed so as to eliminate the necessity of tools, particularly special tools, for this purpose, and in this way eliminate any reason for delays in the assembly operations wherein skin clamps are advantageously employed.

Another object of the present invention is the provision of a skin clamp including a perforation entering plunger in a single piece, not only in the interest of more ready manipulation without loss of time, but to eliminate any parts which might, through accumulation of metal cuttings, dirt and other foreign matter, fail to properly function under spring pressure.

With these general objects in mind, further objects as well as the resulting advantages of the invention, will clearly appear in the course of the following detailed description of the invention, with reference to the accompanying drawing which forms a part of. this specification, and in which:

Figure 1 is a side elevation of the skin clamp of the present invention, showing the same in position preparatory to use;

Figure '2 is a vertical longitudinal sectional view showing the same in effective useful position;

Figure 3 is a, horizontal, sectional view taken substantially on line 33 of Figure 1;

Figure 4 is a, detail view, partly in section and partly in elevation, showing the spear head of the plunger in retracted position, and

Figure 5 is a perspective view showing a possible modification.

Referring now to the abovedescribed drawing and particularly to Figures 1 to 4 thereof, it is proposed in the present instance to provide a skin clamp which may be inserted in, and removed from, efiective position in use, by a single movement of the complete device. To do this the plunger, which enters through the aligned openings A of perforated plates B, to hold the latter temporarily, ,or while rivets or like permanent connections are made, consists of a single piece of suitable spring 'wire bent upon itself to form spaced parallel, or substantially'parallel, extensions l0, and a spear-shaped, aperture-penetrating head II, at its bight end. This head, whose rounded extremity may be readily passed through the plate openings A, is of greater width at its inner end than the diameter of said openings and presents at said end angular shoulders l2. When forced through the plate openings, the head ll reduces in width under its inherent elasticity and when the shoulders l2 have passed completely through the openings, 'it expands under tension so as to present its shoulders as clamping members at the far side of the plates B as may be plainly seen by a comparison of Figures 1 and 2.

The other part of the clamp is in the nature of a cup-shaped clamping body l3, including a main cylindrical portion it closed at its lower end by a clamping base i5 and open at its upper end. The base l5 has spaced openings l6 through which the plunger extensions Ill are movable laterally as lengths.

The plunger extends through the body I 3 above its upper open end and is suitably secured at the upper end thereof to a pressure head H, as by embedding the upper angular ends l8 of its extensions If] within the material of the head. The head may be either of metal or suitable plastic material and serves as an abutment for the upper end of a coiled spring l9, surrounding the plunger extensions l0 and compressed between said head and the base l5 of the clamping body I3 upon which its lower end seats.

The tubular clamping body l3 may be expanded or flared at its upper open end, and is preferably provided at diametrically opposite points of said flared end with outstanding fingerpieces or ears 20 which may be grasped when the hand is on plunger pressure head IT, to shift the clamping bod away from the spear head I I of the plunger.

Thus with the extremity of the spear head ll of the plunger within the plate openings A as in Figure 1, and the hand on pressure head I! with the fingers engaging the finger pieces or ears 2!], it is an easy matter to relieve the clamping strain between the shoulders l2 and the clamping base l5, and press the spear head I! through the openings so that upon release of pressure the well as in the direction of their plates B will be effectively clamped between the expanded shoulders l2 and the base i of the clamping body i3, as in Figure 2.

Similarly, to withdraw the clamp, the same pressure on head I! and finger pieces 20 relieves clamping strain of the body and plunger against the plates B, so that it is then an easy matter to pull the spear head ll through the plate openings.

The clamping tension between the clamping body l3'and the shoulders 12 of the plunger is the tension of spring i9'and this tension is at full effective capacity when the device is relieved of hand pressure, although it is not to be understood that the invention is necessarily limited to hand manipulation even though it is so adapted. The finger pieces 20 may be eliminated and the flared upper end 2| of the clamping body 22 of Figure 5 may be utilized as one engaging point of pliers or special tools of this general type adapted to also engage the pressure head I! of the plunger.

In its normal condition of disuse. it is understood that the shoulder head ll of the plunger is held against the base l5 of the clamping body, as in Figure 4, since the shoulders [2 cannot pass through the guide openings l6. Even should they do so the base l5 between openings I6 would prevent withdrawal of the plunger through the clamping body.

It is contemplated that the pressure head H 01' the plunger may be selectively colored to indicate the size of plate openings for which the clamp is intended. 7

Having thus described my invention, what I claim and desire to secure by Letters Patent is:

A' skin clamp including a tubular clamping body having outstanding finger pieces at one end and a clamping base at its other end provided with spaced openings, a plunger including a stem portion through the body, havir; a pressure head beyond the first mentioned end of the body and a shouldered clamping head beyond the clamping base of substantially spear shape, said stem portion and said clamping head consisting of a single piece of U-shaped spring wire the extensions of which are offset adjacent to the lower bight end thereof below the clamping base, and which extensions project upwardly through the openings of the clamping base and have their upper terminals fixed to said pressure head, and a controlling spring around said stem between the pressure head of the plunger and the base of the body. I

GLENN W. PERIMAN. 

